<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="../css/bootstrap.css">
    <title>Bootstrap标题</title>
</head>
<body>
    <!-- small用于创建副标题，放在对应标题标签的内部 -->
    <h1>一级标题 <small>副标题</small> </h1>
    <h2>二级标题 <small>副标题</small> </h2>
    <h3>三级标题 <small>副标题</small> </h3>
    <h4>四级标题 <small>副标题</small> </h4>
    <h5>五级标题 <small>副标题</small> </h5>
    <h6>六级标题 <small>副标题</small> </h6>
    <!-- 显示标题是比普通标题字体更大的标题，但是字会更细 -->
    <!-- 显示标题都是用h1标签，通过类名来控制大小 -->
    <h1 class="display-1">一级显示标题</h1>
    <h1 class="display-2">二级显示标题</h1>
    <h1 class="display-3">三级显示标题</h1>
    <h1 class="display-4">四级显示标题</h1>
</body>
</html>